1. Field of the Invention
The present invention generally relates to an antenna which can be used in wide band communications.
2. Description of the Related Art
Recently, a radio communication technology utilizing UWB (ultra-wide band) has been used. UWB has a radar function, a positioning function, and a radio communication function; and was approved to use the 3.1 to 10.6 GHz band by the US FCC (Federal Communications Commission) in 2002.
UMB is a radio communication technology in which pulse signals are used in an ultra wide band. Therefore, an antenna which is used in UWB must have a structure which can transmit/receive signals in the ultra wide band.
An antenna for use in the 3.1 to 10.6 GHz band approved by the FCC is proposed, which antenna includes a base plate and a power supply body (Non-Patent Document 1).
[Non-Patent Document 1] An Omnidirectional and Low-VSWR Antenna for the FCC-Approved UWB Frequency Band, written and proposed by Takuya Taniguchi and Takehiko Kobayashi, in The General Conference of The Institute of Electronics, Information and Communication Engineers, in 2003.
As a radio communication technology, there are a wireless LAN (local area network) and Bluetooth other than UWB. An antenna using UWB can be used in frequency bands of the wireless LAN and Bluetooth. Therefore, the antenna using UWB (UWB antenna) can be common in plural radio communication technologies including the wireless LAN, Bluetooth, and UWB. Consequently, when a common antenna such as the UWB antenna is used, antenna space can be less than that of plural antennas for various technologies.